MIPS: Remove unused header file m48t37.h

No users -> remove it.
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

arch/mips/include/asm/m48t37.h

-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- *  Registers for the SGS-Thomson M48T37 Timekeeper RAM chip
- */
-#ifndef _ASM_M48T37_H
-#define _ASM_M48T37_H
-
-#include <linux/spinlock.h>
-
-extern spinlock_t rtc_lock;
-
-struct m48t37_rtc {
-	volatile u8	pad[0x7ff0];	/* NVRAM */
-	volatile u8	flags;
-	volatile u8	century;
-	volatile u8	alarm_sec;
-	volatile u8	alarm_min;
-	volatile u8	alarm_hour;
-	volatile u8	alarm_data;
-	volatile u8	interrupts;
-	volatile u8	watchdog;
-	volatile u8	control;
-	volatile u8	sec;
-	volatile u8	min;
-	volatile u8	hour;
-	volatile u8	day;
-	volatile u8	date;
-	volatile u8	month;
-	volatile u8	year;
-};
-
-#define M48T37_RTC_SET		0x80
-#define M48T37_RTC_STOPPED	0x80
-#define M48T37_RTC_READ		0x40
-
-#endif /* _ASM_M48T37_H */